See that little "qe 1/1″ listed on the screenshot above of my DROID RAZR booted into recovery? According to @P3Droid and a variety of testers, this is a root checker of sorts that Motorola has built into the boot and recovery .img files of their current crop of devices, including the RAZR, RAZR MAXX and DROID 4. If you see "qe 0/0″ you are running a device that has never been rooted. If you see "qe 0/1″ you are running a device that was at one time rooted, but currently is not. If you see "qe 1/1″ like in the picture above, you are running a device that is currently rooted.
